Subauroral Luminosity STEVE over Yakutia during a Substorm: Analysis of the Event of March 1, 2017

Strong thermal emission velocity enhancement (STEVE) is a recently identified, narrow, latitudinally extended, a subauroral glow ribbon of purple light. This glow is associated with the subauroral ion drift (SAID). This paper presents data from observations of the STEVE phenomenon that were conducted for the first time in Russia near the zenith of the Maimaga subauroral station (with geomagnetic coordinates 58°, 202°). The glow was registered with a digital all-sky imager equipped with six interference optical filters with effective bandwidth of 2 nm. The STEVE luminosity arose ~40 min after the onset of the substorm expansion phase that was more polar than the preexisting SAR arc. During the combined equatorial motion, the STEVE region reached the red arc. The STEVE luminosity began with the appearance of inhomogeneities moving westward. The STEVE thermal emission with a local enhancement of the 630.0 nm emission [OI] was caused by SAID. In our case, the SAID signature was the velocity of the westerly motion of inhomogeneities, ~840 m/s. Approaching the station zenith, the inhomogeneities merged into a continuous strip and then into a narrow glowing ribbon STEVE existed ~1 h, and shifted equatorward by ~190 km. In the continuous emission spectrum, the red emission line [OI] dominated. The STEVE luminosity height was calculated.